The invention relates in general to data processing systems for real-time, multi-dimensional analysis and display. More particularly, the invention is directed to a real-time processing system that processes multi-dimensional signals received from a passive acoustic surveillance system.
Prior art monitoring systems typically receive data from a beamformer and an array of hydrophones which are dragged behind, or mounted on, a vessel. The data received from the beamformer is the amplitude of the acoustic energy, within a frequency band, at a specified angle (or "bearing"), and at a discrete time interval.
Various techniques are currently used to process this data to detect and track submarines. Although the data inherently is three-dimensional, having correlative values for frequency, time and bearing, known systems analyze the data in two dimensions only, and therefore must sacrifice data analysis in one of these dimensions.
Some prior art systems perform data calculations on data in a "LOFAR" format. LOFAR data is the amplitude of the data received at a particular bearing in a time by frequency format. These prior art systems therefore can analyze data from only one direction, or bearing, at a single time, and cannot correlate data across several bearings while maintaining the bearing data separately.
Other prior art systems arrange the same data in a "FRAZ" format, or a frequency by aximuth matrix. This allows data processing of data from all directions for a particular frequency range, but only for one particular time interval. Additional prior art systems arrange the data in a "BTR", or bearing by time format. This allows data processing of data from many directions over time, but only for a limited frequency band or frequency bands.
Current monitoring systems usually receive noise and other unwanted signals that obscure signals of particular interest. In a sonar processing system deployed on an ocean-going vessel to detect and track other vessels, the system typically receives signals from natural sources such as wind and waves, from merchant shipping, and from its own vessel. These sonar signals frequently obscure signals of particular interest, such as from a submarine.
The present invention is not limited to processing sonar signals. Digital images can be formed from a variety of input data signals, including seismics, radar, radio, video and film. Because digital images require a very large amount of data storage, it is difficult to process digital images on a real-time basis. Currently no systems provide for high-resolution processing and display of three (or higher) dimensional images on a real time basis.
In other applications, it would be useful to be able to transmit a multi-dimensional image to a remote location. Because a digital image involves a large amount of data, real-time transmission of a multi-dimensional image is impractical in current systems.
It is therefore an object of the present invention to provide a multi-dimensional image processing system that operates in "real-time".
It is a further object of the invention to provide a multidimensional image processing system that allows the suppression of certain objects and the enhancement of other objects in order to "focus-in" on an object or objects of interest.
Yet another object of the invention is to provide a multidimensional image processing system that compresses data for remote transmission, and then reconstitutes the received data to accurately represent the original image.
It is also an object of the invention to store data in a compressed form which can be rapidly and efficiently searched or later retrieved and used to generate data in an uncompressed form.